Synthetic fiber materials are used in a variety of surgical applications that involve tissue and cell ingrowth and adhesion. The recent use of synthetic fiber-based implants as tissue scaffolds for the regrowth of damaged tendons and ligaments is a notable example. Often these tissues and fiber materials are subjected to mechanical stress. However, little is known concerning the process of cell adhesion to these materials and the effects of mechanical stress on cell adhesion and cell function. The proposed series of experiments is designed to investigate the characteristics of rat tendon fibroblast cell attachment to a variety of synthetic fibers, in vitro, and to investigate the effects of mechanical stress and deformation on these cells. Carbon, Dacron, polyethylene and Nylon fibers of varying diameters, surface characteristics and mechanical properties will be used as substrates. Cell culture techniques, scanning electron microscopy, transmission electron microscopy, immunofluorescent labeling of cell cytoskeleton (anti-actin IgG labeling of stress fibers), reflection interference microscopy and flow viscometry measurement of cell adhesion strength will be used in these experiments. Morphometric methods will be used to evaluate the morphological data. The proposed experiments are designed to investigate: (a) the general morphology, morphology of cell attachment and cell cytoskeleton of rat tendon cells cultured on synthetic fibers of varying compositions and configurations, (b) the strength of rat tendon cell attachment to these fibers, and (c) the effect of mechanical stress and deformation, applied to the fiber substrates, on cell attachment morphology and strength. These experiments will provide valuable information concerning connective tissue cell interaction with a variety of commonly used surgical materials, and information concerning the cellular mechanisms involved with stress-induced remodeling of tissue.